Drugs which are designed to inhibit or delay the coagulation, or thickening of the blood. Most anticoagulants interfere with the formation of thromboplastin, or the conversion of prothrombin to thrombin and with the formation of fibrin from fibrinogen.

Medications that interfere with or inhibit blood from clotting are sometimes recommended for patients with atrial fibrillation or an artificial valve. An example of a weak or mild anticoagulant is aspirin. An example of a more powerful anticoagulant is warfarin or coumadin.

Blood Thinners...medications which reduce or impair the ability of the blood to form clots. These medications are used to retard clot formation on artificial devices or in certain. The most common medications are oral warfarin (or Coumadin®) and intravenous heparin .